When using the TTY setting is enabled in
POST /containers/create,
the stream is the raw data from the process PTY and client's stdin.
When the TTY is disabled, then the stream is multiplexed to separate
stdout and stderr.

The format is a Header and a Payload (frame).

HEADER

The header contains the information which the stream writes (stdout or
stderr). It also contains the size of the associated frame encoded in the
last four bytes (uint32).

It is encoded on the first eight bytes like this:

header := [8]byte{STREAM_TYPE, 0, 0, 0, SIZE1, SIZE2, SIZE3, SIZE4}

STREAM_TYPE can be:

0: stdin (is written on stdout)

1: stdout

2: stderr

SIZE1, SIZE2, SIZE3, SIZE4 are the four bytes of
the uint32 size encoded as big endian.